In current apparatus for forming cross-lapped webs, for example the machine shown in U.S. Pat. No. 3,558,029 to Manns, a thin, narrow width strip of carded material, herein referred to as "batt", is folded to convert it into a web which is thicker than the batt, and whose width is, as a rule, different from and usually greater than the width of the batt. Such known web manufacturing machines include a feed system for the batt, a guide system which receives the batt as it leaves the feed system and causes the batt to move along a loop-like path, and a delivery conveyor onto which the batt is placed as it leaves the guide system.
The guide system of the foregoing machine comprises two aprons or endless belts which run on rollers carried on upper and lower moving carriages that are transversely reciprocatively driven relative to the delivery belt. The aprons or belts of the guide system are driven relative to the carriages to move the batt strip through its path from the feed system to the delivery belt, and the delivery belt moves at a continuous rate of advance in a direction perpendicular to the directions of movement of the carriages. Consequently, the batt is placed on the delivery belt in consecutive transverse folds or plies. The relationship between the speed of the delivery belt and the speed of the lower carriage determines the number of overlapping folds and therefore the thickness of the final web. The width of the web is defined by the travel of the lower carriage.
One disadvantage of the foregoing known machine results from the reciprocation of the guide carriages. Such reciprocation produces air eddies above the delivery belt which, in turn, produces eddying of the batt and web on the delivery belt, leading to irregularities in the final web.
One attempt to overcome the air eddying problem may be found in U.S. Pat. No. 3,877,628 to Asselin et al. This patent also describes a machine for forming cross-lapped webs that includes upper and lower transversely reciprocative carriages, a delivery belt positioned beneath the lower carriage and longitudinally movable relative thereto for receiving the batt strip, and first and second guide aprons or conveyor belts which deliver the batt from a feeding device to the delivery belt. In this case the return runs of the guide aprons or belts are juxtaposed above the strip of batt being deposited on the delivery belt so as to shield the just delivered batt from air eddies.
The guide aprons or belts in the foregoing machine are separately driven relative to the cross-lapping carriage so that when the carriage is moving in one direction to deposit the batt strip on the delivery belt, the trailing run of the guide apron has a relative transverse speed of zero with respect to the batt strip being laid on the delivery belt; however, the guide apron on the opposite side of the carriage has a transverse speed relative to the batt strip and web thereunder that is twice the speed of the carriage. The latter guide apron thus drags across the fragile batt strip and web deposited thereunder, tending to disturb the same and making it impossible to achieve a uniform density profile in the web. This disadvantage is magnified if the dragging apron contains any contamination, such as dirt, fibers or oils, on its surface.
It is, therefore, a primary object of the present invention to provide improved apparatus for forming a layered, cross-lapped web of predetermined width from a strip of batt material.
Another object of the present invention is to provide an improved apparatus for forming a layered, cross-lapped web of predetermined width from a strip of batt material, in which the batt strip and web deposited on the delivery conveyor are shielded from air eddies generated by the movement of the cross-lapping carriage relative to the delivered batt.
A further object of the invention is to provide an improved apparatus for forming a layered, cross-lapped web of predetermined width from a strip of batt material, in which the batt strip being delivered by the cross-lapping carriage to the delivery conveyor and the fragile web on the delivery conveyor are shielded by aprons or conveyor belts that are transversely static relative to the deposited batt strip and web.
Additional objects and advantages of this invention will become apparent as the following descriptions proceeds.